The present invention relates to improved trolling apparatus and particularly to a trolling wire therefor.
When trolling in relatively deep waters, it is desirable to use a trolling line with a heavy weight to hold the end of the line at a desired depth. Typically a fishing line is releasably coupled to the trolling line to maintain a fishing lure at the desired depth while trolling and provide normal play of the line once the fish strikes and the line separates from the trolling line. Recently electrically driven trolling reels have been developed, one such apparatus being described in detail in U.S. Pat. No. 3,922,808 issued on Dec. 2, 1975 and assigned to the present assignee.
As is well known, many species of fish prefer known temperature waters and the trolling apparatus described in the above identified patent incorporates a trolling line which is an electrical conductor permitting the mounting of a temperature responsive element at the end thereof for reading the temperature of the water. U.S. Pat. No. 3,916,555 issued Nov. 4, 1975 and assigned to the present assignee, also discloses a trolling apparatus utilizing such an arrangement together with a two conductor cable employed as the trolling line.
Considerable difficulty, however, has been encountered using commercially available or even specially made cables in the trolling apparatus environment. Since the cable can extend to 200 feet or even more, it must be of a relatively small diameter to fit on a compact trolling reel suitable for the sport fisherman. On the other hand, the tensile strength must be relatively high since there are significant tension forces on the line when it is payed out a significant distance and especially if the line snags. Also and particularly in saltwater, the wire tends to become short circuited due to the seepage of water between the conductors of the cable. With prior art cable, the addition of an outer insulating and protective jacket causes the cable to be relatively bulky and unsuitable for use in a compact trolling apparatus. Prior art cable frequently had an outer diameter of about 0.080 inches and yet a tensile strength of only 100-125 pounds.